Engine starting mechanism



Nov. 16, 1943.

H. A. THORNBURG 2,334,657 ENGINE STARTING MECHANISM Filed July so, 1942 4 Sheets-Sheet 1 Nov; 16, 1943.

H. A. THORNBURG ENGINE STARTING HECHANISI 4 Sheets-Sheet 2 Filed July 30, 1942 -1 .6, 1943. H. A. THORNBURG 7 2,334,657 mamas STARTING MECHANISM Filed July 30. 1942 4 Sheets-Sheet 3 Nov. 16, 1943.

H. A. THORNB'URG ENGINE STARTING MECHANISM Filed July so. 1942 I 4 Sheets-Sheet 4 Patented Nov. 16, 1943 ENGINE STARTING MECHANISM Herbal A. Thornburg, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware v Application July 30, 1942, Serial No. 452,833-

14 Claims.

This invention relates to a mechanism for starting an internal combustion engine, particularly aircraft engines.

It is an object of the present invention to provide for the starting of the engine either by electric motor or by hand-cranking, the effectiveness of either of these instruments being augmented by the release of. energy stored in a flyand this object is accomplished by providing means for yieldably connecting the flywheel withthe coupling so that the flywheel may gradually take up its burden of supplying additional power for starting the engine.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the invention is shown.

In the drawings:

Fig. 1 is a longitudinal sectional view of an engine starter mechanism mbodying the present invention.

Fig.2 is a fragmentary, longitudinal, sectional view on line 22 of Fig. 1.

Figs. 3, 4, 5, 6, 7, 8 and 9 are sectional views taken respectively on lines 3-3 of Fig. 1, 4-4 of Figs. 1 and 2, 55 of Figs. 1 and 2, 6-8, 1-1, 8-8 and 9-9 of Fig. -1.

Fig. 10 is an end view looking in the direction of arrow |8 of Figs. 1 and 2, the part shown in section being taken on line |8-|8 of Figs. 1 and 2.

The starter mechanism is enclosed by a housing comprising a right end part 28, an inter mediate part 2| and a left end part 22, these parts having abutting flanges clamped together by screws 23. Housing 22 has a cylindrical portion 24 adapted to extend through a hole, not shown, in the frame of an engine, said hole being concentric with respect to a coupling member, not shown, carried by the engine. Housing 22 provides a flange 25 having holes 28 for receiving screws by which the housing 22 and the entire starting unit is attached to the'engine frame.

Housing 28 has a tubular part 38 having. stepped bore portions 3| and 32 joined by shoulder 33. The bore 3| receives aring 34 which encloses an outer bearing race 35 supporting bearing balls 38 which support an inner bearing race 31. -Race 35 engages a flange 38 01 ring 34, and flange 38 of ring '34 engages shoulder 33 of part 38. Flange 38 is held in engagement with shoulder 33 by a spacer sleeve 48 which iscounterbored ata'4l to receive the outer race 42 of a bearing which includes bearing balls 43 and an inner race 84. These ball bearings support a shaft 58 inte gral with a bevel gear 5| and connected by pin 52 with a coupling 53 adapted to be connected with a flexible shaft driven by an electric motor, not shown. The inner race 31 issecured between a shoulder 54 of shaft 58 and a washer 55 by a nut 58 threadedly connected with the shaft 58 and having a plurality of notches 51 each for receiving a tang 58 of the washer 55 which is bent around the nut and into one of the notches in order to prevent the nutfrom turning. A plurality of screws 88 secure to the housing part 38 a circular plate 6|, which retains the spacing sleeve 48 and the bearing race 42. Plate 6| has an aperture 62 to provide clearance for an oil seal disc 83 which is press-fitted into the race 42 and which is provided with a central aperture through which the shaft 58 projects. The plate 83 retains a felt ring 84 against the bearing race Gear 5| meshes with gear 18 which is splinedly connected with a hub H which is axially adjustable along the shaft 12 and which is drivingly connected therewith by key 13. The hub II is splinedly connected with a dished washer 14 of resilient metal engaging the crown of an anvil or fulcrum washer 15 (Fig. 9) which is not splined to the hub] l. Due to the action of the resilient washer 14 the anvil washer I5 is caused to bear frictionally against the right face of gear I8, and the left face of gear 18 is caused to bear against a washer 18 (Fig. 8) which is splined to the hub II and which bears frictionally against the right face of a ring gear Tl having a hub I8 surrounding the shaft 12. The washer l4 urges the left end of hub I8 against a shoulder 18 of shaft'12.

- of a nut 85 threaded upon the right end of shaft 12. r A spacer sleeve 88 separates the inner race 8| from the hub 1|. The tightening of nut 85 causes the shaft 12 to be urged toward the right relative to the bearing race 8|, thereby in effect urging the resilient disc 14 toward the left to cause the gear I8 to be resiliently connected with the gear I1 through frictional resistance. The nut 85 is secured in the desired position of adjustment along the' shaft 12 by bending the tang 83 of washer 82 into one of the notches 84 of the nut.

The outer race 81 of ball bearings 88 is received by a sleeve 88 and is retained therein by a resilient split washer 88. Sleeve 88 is pressed into the tubular extension 88 of a cover plate 8| for covering a hole in the right end of housing 28. Plate 8| is secured to housing 28 by a plurality of screws, one of which is shown at 82.

Cover 8| provides a recess 88 for receiving a solenoid unit comprising a magnetizable housing 84 attached-to a flanged ring 85 which is secured to the cover 8| in anysuitable manner. The magnetizable solenoid housing 84 supports a magnetizable core 88 which supports a nonmember 2 I.

magnetizable tube 91. Between the tube 91 and the housing 94 is located an annular magnet coil 98 which is insulated from these parts. Coil 98 is retained by non-conducting disc 99 apertured to receive the leads from the coil, one of which is shown at I00. The non-magnetizable tube 81 supports and guides for sliding movement an armature I III attached to a rod I02 which is slidable within the central bore of the shaft 12. Solenoid housing 94 is attached to aplate I 02. Between plate I02 and armature IOI there is located a compression spring I03 which urges the armature IOI toward the right so that it engages a felt or leather bumper disc I04 located against a cup-shaped member, attached to housing 04 by a retainer disc I06. When solenoid coil 98 is connected with a current source, armature IOI moves toward core 36 to cause rod I 02 to move toward the left for the purpose of coupling the starter mechanism with the engine to be started, as will be explained in detail later. When the solenoid 08 is disconnected from the current source, spring I03 returns the armature IN and the rod I02 to the position shown in the drawing.

I'he ring gear 11 meshes with an idle gear IIO journalled on needle bearings I II which are journalled on a stud II2 attached to a bracket arm II3 integral with a ring II4 attached by screws H to the housing 20. Idle gear H0 is retained upon the stud II2 by washer I I6 attached to stud II2 by screw 1. Idle gear IIO meshes with a gear I25 integral with a hub I2I journalled on needle bearings I22 supported by the hub 16 of gear 11. Hub I2I is integral with flywheel rim I 23 rotatable in an annular pocket I24 located between housing parts and 2|. A washer I25 spaces the right end of hub I2I from the left face of gear 11. Washers I26 space the left end of hub I2I from shoulder 18.

Shaft 12 has an eccentric portion I30 whic receives an inner bearing race I3I of bearing balls I32 having an outer race I33. Race I3I is confined between a shoulder I34 and a washer I35 retained by a plate I36 attached to the eccentric by screw I31. Plate I36 is integral with an eccentric counter-balance I38 integral with a plate I39 apertured to receive the shoulder 11. Outer race I33 is located between a shoulder I40 of a hub Ill and is retained by resilient split ring I42.

shoulder I65 of frame 22 with a snap ring I66 secured to said left outer bearing I59. Movement of said left outer race I59 toward the left is limited by a retainer I61 attached by screws I68 to frame22. Retainer I61 carries an oil seal comprising parts HI and I12 enclosing a felt seal ring I10 urged by a garter spring I13 against the sleeve I 56. Movement of left inner bearing race I51 toward the left is limited also by a resilient split ring I15 engaging a groove in the sleeve I56.

Sleeve I 56 is internally splined at I80 and receives an externally splined stop block I8I. Spline I80 .also engages similar splines of the hub I82 of a jaw clutch I 83 or driving member for engaging a driven jaw clutch, not shown, connected with the engine to be started. The location of the clutch I83 relative to the sleeve I56 is determined by the adjustment of a nut I90 threaded on rod I02, the sleeve I82 being urged against the nut I90 by compression spring I9I bearing also against the block I8 I.

Referring to Figs. 1 and 4, the hub I53 is journalled on shaft 12 by a ball bearing I53a retained in hub I53 by a resilient split ring I53!) and uponshaft 12 by a washer I530 and a nut I53d (thread ed on shaft 12) having notches I53f one of which received a tang I53e of washer I53c.

When the solenoid is energized, the rod I02 moves toward the left to permit the jaw clutch I83 to move toward the left underthe action of spring I3I in order to engage acompanion jaw clutch member of the engine to be started. When the engine becomes self operative so that. the driven jaw clutch member with which it engages tends to run ahead, the jaw clutch member I83 The hub m is integral with epicyclic gears 14:

and I44 meshing respectively with ring gears I45 and I46. Gear I45 has splines I41 engaging similar splines I48 (Fig. 6) provided by frame Gear I45 is retained against a shoulder. I49 .of member 2I and a spacer ring I50 which is retained by a plurality of spacer lugs I5I integral with frame member 22. Ring I50 is the outer'bearing race of a roller bearing I52, the inner race-of which is provided by ring gear I46 which has a hub I53 splinedly connected at I54 with a cup-like rotary member I55 which isintegral with a tubular extension or sleeve I56 fitting within inner race I51 of ball bearings I56 whose outer races I53 are supported by a sleeve I63 carried by frame I22. The part I55 provides a shoulder I6I engageable with bearing race I51 and limiting its movement toward the right. Movement of bearing race I55 toward the left is limited by the engagement with a shoulder I63 provided by frame 22 of a resilient wire sn'ap ring I82 received by a groove in the race I59. Movement of the left outer bearing race I59 toward the right is limited by the engagement with a is disengaged drivingly from the engine and merely snaps back and forth under the action of spring I9I. When after starting the engine, the solenoid is deenergized, spring I03 within the solenoid unit restores the jaw clutch I83 to normal position.

The mechanism which has been described and its enclosed housing constitute a unit which is mounted upon the vehicle propelled by the engine to be started. Preferably the unit is mounted upon the frame of the engine. The starting motor, which may be carried on a small truck together with its currentsource such as a storage battery, is connected with the starter mechanism by means of a flexible shaft and'a coupling which engages the coupling 53. Before the sole hold is energized the electric motor is connected with its current source and is caused to rotate the driving clutch member I83 and the flywheel I23. After the flywheel has attained a certain high speed, resulting in the storing of kinetic energy therein, the circuit between the current source and the solenoid magnet 38 is completed, thereby causing the rod I02 and the driving clutch I83 to move toward the left to connect with the driven clutch, not shown. -At the instant these two clutch members become engaged, there is a tendency to reduce the speed of the starter drive mechanism, but the flywheel I23 tends to continue to rotate and its frictional connection with the mechanism to the ring gear 11, washer 16 and bevel gear 10 provides means for yieldablyslippage of the' friction clutch between the flywheel I23 and the shaft 12 gradually diminishes, during which time the flywheel is imparting stored energy to the shaft 12 gradually to increase its speed. The nut 85 at the right end of shaft 12 is so adjusted that a limited amount of torque is transferred from the flywheel I23 to-the shaft 12 by the friction clutch between gears I1 and 10. Thus the shaft "is allowed to receive a limited amount of energy from the flywheel; and, therefore, the mechanism is not stressed abnormally at the instant the driving clutch member I83 becomes drivingly connected with its companion clutch member of the engine to be started. The torque. which is initially transmitted is only suflicient when combined with the torque of the starting motor to gradually increase the speed of the driving clutch I83. As acceleration of that member proceeds, more and more of the kinetic energy of the flywheel is given up to assist the starting motor in increasing the speed of the starting mechanism.

In'case an electric motor is not available, the engine may be started manually by hand crank ing the shaft with the ring gear, said clutch including a driven friction element provided by the ring gear, and. driving friction element splinedly connected with the shaft and a spring for'urging the friction elements into engagement under yielding pressure, and means for drivin the shaft.

3. An engine starter mechanism comprisin a shaft,--a driving member for engaging a driven which can be connected with a coupling 200, Fig. v

10, attached to a shaft 2 journalled in bearings 2|2 and 2l3 supported by tubular portion 2 of frame member which provides a housing 2l5 for a gear 2 l6 integral with shaft 2 and driving a gear 2. The manner of supporting and re-. taining the bearings 2|2 and H3 of the shaft 2| I is exactly similar to the manner of supporting the bearings 36 and 43 of shaft 50, shown in Fig. 1. Gear 2H is integral with a shaft 218 supported by needle bearings 219 in a tubular portion 220 of frame 20. The leftend of portion 220 is attached by screws 22! (Fig. 2) to a pad 222 which is integral with frame member 2 I. Pad

222 is secured by screws 223 to an extension of frame 22. The space between frame 22 and pad 222 (Fig. 2) receives a gear 224 driven by shaft 2!!! and retained thereon by nut 225. Gear 224 meshes with gear 226 which is integral with the cup shaped part I55 which provides the sleeve I56. By turning a hand crank (not shown) connected with coupling 200, the starter drive mechanism and the flywheel I23 are caused to rotate; and, when a certain flywheel speed has been attained, the solenoid is energized so as to connect the hand crank and the flywheel with the engine through the driving clutch member I83.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An engine starter mechanism comprising a shaft, a driving member for engaging a" driven member of the engine to be started, a flywheel, speed reducing gearing connecting the shaft with the driving member, a ring gear having a hub journalled on the shaft, a flywheel having a hub journalled 'on the ring gear and provided with a gear, an idle gear connecting the ring gear with the flywheel-hub gear, a friction clutch connecting the shaft with the ring gear, said clutch in cluding a driven friction element provided by the ring gear, and means for driving the shaft.

2. An engine starter mechanism comprising a shaft, a driving member for enga g a driven member, of the engine to be started, a flywheel, speed reducing gearing connecting the shaft with the driving member, a ring gear having a hub journalled on the shaft, a flywheel having a hub journalled on the ring gear and provided with a gear, an idle gear connectingthe ring gear with the flywheel-hub gear, a friction clutch connectmember of the engine to be started, a flywheel, speed reducing gearing connecting the shaft with the driving member, a ring gear having a hub journalled on the shaft, a flywheel having a hub journalled on the ring gear and provided with a gear, an idle gear connecting the ring gear with the flywheel hub gear, a friction clutch connecting the shaft with the ring gear, said clutch including a driven friction element provided by the ring gear, a gear for driving the shaft and splinedly connected therewith, a clutch driving element splinedly connected with the shaft and located between the ring gear and the shaft driving gear, and a spring for urging the shaft driving gear against the clutch driving element and the latter into engagement with the clutch driven element provided by the ring gear.

4. An engine starting mechanism comprising a shaft, a driving member for engaging a driven member of the engine to be started, a flywheel,

speed reducing gearing connecting the shaft with the driving member, a ring gear having a hub journalled on the shaft, a flywheel having a, hub

journalled on the ring gear and provided with a gear, an idle gear connecting the ring gear with the flywheel hub gear, a hub surrounding the shaft and splinedly connected therewith, a friction clutch connecting the hub and ring gear and including a clutch driving plat splinedly connected with the hub, a clutch driven plate provided by the ring gear, a spring disc secured by the hub and arranged to urge the clutch plates together, means for effecting relative axial movement between the shaft and hub in order to adjust the pressure effected by the spring disc, and means for driving the shaft.

5. An engine starting mechanism comprising a shaft, a driving member for engaging a driven member of the engine to be started, a flywheel,

gearing for connecting the shaft with the driving member, means supporting the shaft for axial movement, means for adjusting the shaft axially, means for connecting the shaft and flywheel and including a friction clutch having driving and driven plates which are movable axially with the shaft when the latter is adjusted, a spring having a part fixed against movement with the shaft and a part for exerting pressure on the clutch plates, said pressure being varied when the shaft is axiallyadjusted, and means for driving the shaft. 4

6. An engine starting mechanism comprising a shaft, a driving member for engaging a driven member of the engine to be started, gearing for connecting the shaft with the driving member,

'means supporting the shaft for axial movement,

on the clutch plates, said pressure being varied when the shaft is axially adjusted, and meana for driving the shaft.

7. An engine starting mechanism comprising a shaft, a driving member for eng a d v n member of the engine to be started, a gearing for connecting the shaft with the driving member, means supporting the shaft for-axial movement, means for adjusting the shaft axially, a flywheel movable axially with the shaft and rotatable thereon, speed increasing gearing for connecting the shaft and flywheel and including a gear movable axially with the shaft and rotatable thereon, a friction clutch having a driven plate provided by the gear and a driving plate connected with the shaft, a spring having a part flxed against movement with the shaft and a part for exerting pressure on the clutch plates, said pressure being varied when the shaft is axially adjusted, and means for driving the shaft.

8. An engine starting mechanism comprising a shaft, a driving member for engaging a driven member of the engine to be started, gearing for connecting the shaft with the driving member, means supporting the shaft for axial movement, means for adjusting the shaft axially, a flywheel movable axially with the shaft and rotatable thereon, speed increasing gearing for connecting the shaft and flywheel and including a gear movable axially with the shaft and rotatable thereon, a friction-clutch having a driven plate provided by the gear and a driving plate connected with the shaft, a hub splinedly connected with the clutch driving plate and splinedly connected with .the shaft and fixed against axial movement, a

spring washer having its central part supported by the hub and its peripheral part exerting pressure upon the clutch plates, said pressure being varied when the shaft is axially adjusted, and means for driving the shaft.

9. An engine starting mechanism comprising a shaft, a driving member for engaging a driven member of the engine to be started, gearing for connecting the shaft with the driving member, means supporting the shaft for axial movement, means for adjusting the shaft axially, a flywheel movable axially with the shaft and rotatable thereon, speed increasing gearing for connecting the shaft and flywheel and including a gear movable axially with the shaft and rotatable thereon, a friction clutch having a driven plate provided bythe gearand a, driving plate connected with the shaft, a hub splinedly connected with the clutch driving plate and splinedly connected with ;the' shaft and fixed against axial movement, ,a spring washer having its central part sup rted by the hub and its peripheral part 'exe g pressure upon the clutch plates,

11. An engine starting mechanism comprising a shaft, means for adjusting the shaft axially, a member for driving the shaft, an engine driving member for engaging a driven member of the engine to be started, a rotary member fixed against axial movement and supporting the engine driving member, speed reducing gearing for connecting the shaft and rotary member and including epicyclic gears eccentrically driven by the shaft and ring gears meshing therewith, one of the ring gears being fixed and the other rotatable around the shaft, said epicyclic gears and the rotatable ring gear being axially movable with the shaft when the latter is adjusted, a bearing supporting the ring gear and permitting axial movement thereof, a bearing supported by the ring gear and supporting the shaft and mova-ble axially therewith, a spline connection between said first mentioned rotary member and the rotatable ring gear, a flywheel, a friction clutch for connecting the flywheel with the shaft, and means for varying the torque transmitted by the clutch in response to axial adjustmentof the shaft.

12. In an engine starting mechanism the combination of a shaft, means for driving the shaft, a member connected with the engine to be started, speed reducing gearing connecting the member with the shaft and comprising adjacent epi-' cyclic gears driven eccentrically by the shaft,

adjacent ring gears meshing respectively with the epicyclic gears, a fixed annular member surrounding the ring gears and supporting one for non-rotary and the other rotary movement, a

flywheel having a hub supported by the shaft coaxially therewith and having a rim surrounding a portion of the fixed annular member, and means for connecting the flywheel with the shaft.

13. In an engine starting mechanism the combination of a shaft, means for driving the shaft,

a member connected with the engine to be started, speed-reducing gearing connecting the member with the shaft and comprising adjacent epicyclic. gears driven eccentrically by the shaft,

r adjacent ring gears meshing respectively with the epicyclic gears, a flxed annular member surrounding the ring gears and supporting one for non-rotary and the other rotary movement,'a

flywheel "having a hub supported by the shaft coaxially therewith and having a rim surrounding a portion of ,the fixed annular member, a speed increasing gearing for connecting the shaft with the flywheel and including a ring gear driven by the shaft and surrounding the hub of said pressure being varied when the shaft is axi-' ally adjusted, and a ,gear for driving the shaft and connectai' with the hub.

10. An engine starting mechanism comprising I a shaft, means for adjusting the shaft axially,

a member driving'the shaft,\ an engine driving member for engaging a driven member of the engine to be started, a rotary'v member fixed against a'xial movement and supporting the'engine driving member, speed reducing gearing for con ting the-shaft and rotary member and including rotatable members movable axially with the shaft when the latter is adjusted and having a spline connection with the first mentioned rotary member, a flywheel, a friction clutch for connecting the flywheel with the shaft, and

the flywheel and having a hub located within the hub of the flywheel and surrounding the shaft, a housing surrounding the flywheel and ring gear, a bracket supported by the housing in-the plane of the hub of the flywheel, an idle gear connected with the second mentioned ring gear and a gear on the flywheel hub meshing with the idle gear.

14. In an engine starting mechanism the combination of a shaft, means for driving the shaft, a member connectible with the engine to be started, a flywheel coaxial with the shaft and comprising a disc, a rim extending from one side of the disc and a hub extending from the other side of the disc, speed-reducing gearing at least partly surrounded by the flywheel rim and conmeans for varying the torque transmitted by v the clutch in response to axial adjustment of the shaft.

necting the said engine-connectible member with the shaft, and speed increasing gearing at least partly surrounding the hub of the flywheel for connecting the flywheel with the shaft.

, HERBAL A. 'I'HORNBURG. 

